1. Field of the Invention
The present invention relates generally to an electronically steered radio frequency beam transmitted by a phased array blade antenna assembly for use on an airborne platform whose mission is electronic warfare. The electronically steered radio frequency beam is dynamically directed to either the left or right side of the airborne platform in order to directionally maximize the power of the radiated radio frequency signal.
2. Description of the Prior Art
The industry has a number of airborne antennas used with different airborne amplifiers and covering a broad range of frequencies. However, most of the antennas, especially those covering lower frequency bands, provide less than optimal pattern coverage and thus reduced Effective Radiated Power (ERP) performance. An attempt to address these problems can be found in a U.S. Pat. No. 7,280,083 issued to this inventor. Although the '083 patent reference provides added benefits of good impedance stability versus frequency and stable monotonic antenna pattern characteristics in proximity to an irregular ground plane, the overall design approach imposes the following limitations: the design has an inherent bidirectional antenna pattern vice a unidirectional antenna pattern, a lower amount of radiated power is directed towards the intended target as a result of the bidirectional antenna pattern, the antenna pattern is fixed to radiate symmetrically from the host platform vice a left only or right only radiation pattern, the phased array blade antenna described in the '083 patent reference is not capable of switching the direction of radiation in response to control commands and most importantly, the reference results in a lower gain and thus a shorter standoff distance between a jammer and a target.
There are no known airborne antenna designs in the prior art that will operate in the desired frequency range, at the desired power level, respond to main lobe directional control commands and increases the standoff distance between the jammer and the target. The increased standoff distance provided by the directionally controlled antenna pattern is important in raising the probability of mission success by moving the jamming aircraft further from potential threats. In addition, the unidirectional antenna pattern provides enhanced control of undesirable ownership EMI effects and a potential of significant fratricide reduction.